Ignition coil



Feb. 18, 1947. F BQRGERD ETAL 2,416,148

IGNITION COIL Filed May 27. 1944 Patented Feb. 18, 1947 UNITED STATES PATENT OFFICE IGNITION COIL Harvester Company, Jersey Application May 27, 1944, Serial No. 537,560

el Claims.

This invention relates to an ignition coil. More specifically, it relates to improvements in induction coils and particularly to the type used for ignition in internal combustion engines. The principal object is to provide an improved induction coil structure entirely housed in an improved metallic casing. A more specific object is to provide an enclosure structure for induction coils which may be readily and permanently sealed Without use of solder and objectionable means.

Another object is to provide an enclosure structure for induction coils consisting of two substantially cup-shaped portions which may be hermetically sealed together by securing flanges on the cup-shaped portions together.

The above objects and others which will be apparent from the detailed description to follow, are obtained by a construction such as shown in the drawing, in which Figure l is an elevation View of a coil embodying the invention;

Figure 2 is a section taken through the center of the coil of Figure 1;

Figure 3 is a section taken on line 3 3 of Figure 2; and

Figure 4 is a detail View showing a modification.

Referring to Figures 2 and 3, an inner core structure lil is formed from a plurality of thin metallic laminations ruiming lengthwise of the core. As Will be observed in Figure 3, a plurality of the laminations are stacked together in one direction with additional laminations II being tted on each side. This construction leaves triangular shaped openings I2 at each corner and openings I3 along the at dimension of the laminations when the core is inserted in a tube I4 of insulating material.

A secondary coil I5 of conventional construction is fitted over the tube I4. Said coil terminates spaced from the ends of the tube I4, said tube being also spaced from the ends of the core I A section l5 of paper insulation projects at each end of the secondary coil I5 for holding the coil in position, as Will be hereinafter described.

Tubes I'I of insulating material surround the secondary coil I5. The primary coil I8 is Wound around the insulating tubes Il. A layer of insulating material is wound around the outside 2 of the primary coll i8. A slitted sheet steel member I9 is fitted around the said insulating layer for carrying the outer portion of the magnetic path, the core lll being the inside magnetic path.

Outside the slitted sheet steel member I9, two cup-shaped members 28 and 2i are closely itted. Said cups directly contact the member I9. The member 20 has a rounded bottom portion 22 terminating in the conical flange Said ange is imbedded in a member 2f! formed or any suitable insulating material. Said member is preierably formed of molded Bakelite with suitable asbestos or other heat-resisting fillers. rThe member 24 carries imbedded in proper position a pair of primary terminals 25 and 2i?. in the usual process oi manufacture the terminals 25 and the flange 23 of the member 2t would be molded into position during formation oi the member 2li. Bores 2l extending through a portion of the terminals 25 and 2t and through portions of the member 24 provide means for leading the primary coil terminals 23 out of the coil and for electrically securing them to the terminals 25 and Q, Adjacent the center of the coil the member 2B is provided with an outturned flange 29.

As illustrated in Figure 2, the iiange 2Q is in alinemeni-l with and spaced from a similar iiange 3B formed on the member 2l. A gasket 3l between said flanges provides a sealing means when a securing member 32 is spun over the flanges 29 and 3B. This construction may be varied as illustrated in Figure 4i, which shows anges 2Q and 3U secured together by seam welding. The flanges may belpressed into contact and welded together by a continuous seam around the coil Without the generation or" heat, which would adversely affect the coil structure.

The member 2l is provided with a curved bottom portion 3i' terminating in a conical iiange 32' which is imbedded in a member 33 formed of insulating material, preferably of a molded Bakelite or similar material. Said member is formed in the usual ridge 3 to provide a long ow path and to prevent short-circuiting of the high-tensioned current. A metallic secondary terminal member 35 is imbedded centrally in the member 33 preferably during the molding operation. A metallic member 35 tted in an internal bore or recess Si formedinthe member 33 is provided with a portion $8 which abuts the terminal member 35. The member 3B also abuts the end of the core It. A similar member 39 tted in a recess in the member 34 abuts the other end of the core iii. In the construction of this device the dimensions are so controlled that when the flanges 29 and 3i) are secured together the members 39 and .'i rmly abut the ends of the core. One terminal of the secondary coil is secured to the contact member llt by any suitable means, the other end being in electrical contact, with the housing structure.

Each of the members 2t and 33 are provided with a plurality of circular ridges l i. Said ridges are forced into the end of the paper insulation layers I6 so as to support the secondary winding endwise and, further, so as to make the paper around the ridges more dense and to give long leakage paths for the secondary current from the inside core to the outside slitted sheet metal Wrapping just inside of the housing structure as formed by the members 2G and 2i. The ridges 4i are cut away periodically as at d2 in staggered relationship so that transformer oil, with which the coil is filled, can work from the inside to the outside of the coil, thus giving complete lling over the coil surface.

All of the voids between the i sulation and most of the space in the coil not occupied by solid matter are filled with insulating oil, which keeps out moisture and is a good insulation in itself. The spaces i2 and i3 around the core l0, previously referred to, permit circulation or" the oil so that it may reach all parts of the coil. In the construction of the coil, after the anges at the center have been hermetically closed or joined toegther, the coil is heated with vacuum applied through the terminal outlets after which hot transformer oil is allowed to ll the evacuated space. The coil assembly is then sealed at the terminals while at the elevated temperature. The improved coil structure, and particularly the enclosure or casing therefor, as above described represents a marked advance in coil construction from the standpoint of reliability and the fact that longitudinal seams and complicated joints are voided. Also, the use of solder is eliminated. The two members 2d and 2i are formed as drawn steel cups which may be made from the desired thickness of material. By a simple operation the flanges 23 and 32 can be readily formed, said flanges being properly shaped to give a good, hermetically bond with the molded members and also being of a shape to reinforce and strengthen said members. The center joint may be readily formed either by spinning a member around the flanges as shown in Figure 2, or by seam-welding as shown in Figure 4. The construction also assures rm support of the core i ii and of the Winding within the core, particularly the heavy secondary winding which is held securely by the sections of paper insulation It into which the ridged portions di of the members 2li and 33 are imbedded. l

Applicants claim as their invention all modifications in coil structure falling within the scope of the appended claims.

What is claimed is:

1. An ignition coil comprising a coil, an inner structure including a laminated metallic central core, concentric primary and secondary coils surrounding said coil and terminating spaced from the ends thereof, oil-flow passages extending from end to end of said'structure, a slitted metallic sleeve surrounding said primary coil and a pair girar/is d of housing sections enclosing said inner structure, each of which includes a molded end structure having a recess in which said core extends and axially extending ribs engageable with the coil structure for positioning the same, said ribs being provided with interrupted portions to form oil passages for insulating oil-flow therethrough and through the first named oil passages, said housing sections also including metallic cups having flanges imbedded in the end structures, said metallic cups being tightly tted over said slitted sleeve and being provided with means intermediate the ends of the sleeve for securing the sections hermetically together.

2. An ignition coil comprising a coil, an inner structure including a laminated metallic central core irregular in cross section, an insulating tube tted around said core in contact therewith, the irregular shape of the core providing passages extending lengthwise between the core and the tube, a secondary coil surrounding said core and terminating spaced from the ends thereof, a primary coil surrounding said secondary coil and a housing enclosing said inner structure and including a casing and a molded end structure at each end thereof having a recess in which said core extends and concentric radially spaced laxially extending ribs engageable with the coil structure for positioning the same, said ribs having interrupted portions to provide openings for the i'iovv or" insulating oil therethrough and to the passages along the center core.

3. An ignition coil comprising a coil, an inner structure including a laminated metallic central core irregular in cross section, an insulating tube fitted around said core in contact therewith, the irregular shape of the core providing passages extending lengthwise between the core and the tube, concentric primary and secondary coils surrounding said core and terminating spaced from the ends thereof, and a pair of housing sections enclosing said structure each of which includes a molded end structure having a recess in which said core extends and concentric radially spaced axially extending ribs engageable with the coil structure for positioning the same, said ribs having interrupted portions to provide openings for the iiow of insulating oil therethrough and to the passages along the center core, said housing sections also including metallic cups having flanges imbedded in the end structures and provided with means for securing the sections hermetically together.

4. An ignition coil comprising a coil, an inner structure including a laminated metallic central core irregular in cross section, an insulating tube tightly fitted around said core in contact therewith, the irregular shape of the core providing passages extending lengthwise between the core supply tube, concentric primary and secondary coils surrounding said coil and terminating spaced from the ends thereof, a slitted sleeve surrounding the outer coil and a pair of housing sections enclosing said inner structure, each of which includes a molded end structure having a recess in which said core extends, and concentric radially spaced axially extending ribs engageable with the coil structure for positioning the same, said ribs having interrupted portions to provide openings for the flow of insulating oil therethrough and to the passages along the center core, said housing sections also including metallic cups havin-g flanges imbedded in the end structures, said metal cups being tightly iitted over said slitted 5 sleeve and being provided with means intermediate the ends of the sleeve for securing the sections hermetioally together.

WILLIAM F. BORGERD. FRANK G. MAJER. HAROLD E. KNOPP. LAWRENCE E. BENNETT.

REFERENCES CITED The following references are of record in the le of this patent:

Number Hartzell Aug. 24, 1943 

